What is the main goal of any presentation you give? Engage your audience and make sure they leave knowing the main message of your topic.
Here are some useful tips on how to improve your PPT presentations, and thus, your presentation skills:
PowerPoint for Teachers- PowerPoint Presentations: Design, Content, & Delivery
Death by PowerPoint (and how to fight it)
You'll notice that both presentations have quite a few slides. But, you will see the difference in how the message of the presentation sticks with you. The slides engage and deliver the message.
For some additional tips on how to give effective presentations, check out the Business Week article, The 10 Worst Presentation Habits.
Impliment at least three of anything you learned in these resources above and you're guaranteed to have a happier audience that is bound to be wowed by your ideas!